I. Field of the Invention
The present invention relates generally to a guard extending over the blade chain of a chain saw and, more particularly, to such a guard which is releasably mounted to a forward handle mounted on the chain saw body and adjustable so that the height of the guard above the saw chain can be varied.
II. Description of the Prior Art
As is well known, chain saws include a saw bar projecting outwardly from a motor housing and an endless saw chain is rotatably entrained around the saw bar. The saw chain is necessarily exposed so that it can cut into and through tree limbs, logs and the like. However, only the lower portion of the saw chain adjacent the bottom of the saw bar cuts into the wood and thus, immediately embeds itself within the log. However, the portion of the saw chain along the upper portion of the saw bar remains exposed above the log until the depth of the cut exceeds the height of the saw bar. This exposure of the upper portion of the saw chain creates the risk that the chain saw operator or a co-worker can be severely injured when a portion of the body inadvertently contacts that portion of the saw chain. The risk of such contact is enhanced by the fact that rotation of the saw chain can cause the saw to jump out of the saw cut and toward the chain saw operator or a bystander.
Such risk has always been recognized, although little has been done to avoid such injurious contact other than making the motorized operation of the chain saw smoother and more predictable. Moreover, the use of a guard to protect the upper portion of the saw chain, while leaving the lower portion exposed in order to permit it to contact and cut into the log, has been considered impractical since the width of the saw cut precludes the use of a guard which is wider than the width of the chain when it is necessary to cut a log having a diameter greater than the height of the saw bar. One previously known saw chain guard is disclosed in U.S. Pat. No. 3,344,818 but is particularly designed to cover the saw chain only when the chain saw is not in use since it covers the entire saw chain and saw bar.